Aromatic compositions

ABSTRACT

Process for improving, enhancing or modifying the organoleptic properties of a tobacco product, which comprises adding thereto about 1 to about 1000 parts per million based on the weight of tobacco of octa-3,5-dien-2-one.

This is a divisional of application Ser. No. 482,776, which was filed onJune 24, 1974 now U.S. Pat. No. 3,920,027, which in turn was adivisional of application Ser. No. 219,136, which was filed on Jan. 19,1972 now U.S. Pat. No. 3,840,023.

DESCRIPTION OF THE INVENTION

The present invention relates to compositions and a process forimproving, enhancing or modifying the flavouring properties offoodstuffs, feedstuffs, beverages, pharmaceutical preparations and, moreparticularly, tobacco products.

It is well known that tobacco used for the preparation of cigarettes,for example, is composed essentially of a mixture of different types oftobacco which gives the characteristic flavour and aroma that is desiredin the tobacco smoke produced. Thus, cigarettes currently manufacturedusually contain mixtures of Virginia, Maryland or Kentucky tobacco incombination with oriental or Turkish tobacco.

The respective proportions of the various types of tobacco are varied inorder to obtain the particular flavour and aroma desired. It is alsocommon practice to employ flavouring substances and humectants asadditives to these tobacco mixtures to further enhance the organolepticproperties thereof.

Accordingly, it is an object of the present invention to provide aprocess for improving, enhancing or modifying the organolepticproperties of a tobacco product by incorporating therein an aromaticcomposition or certain synthetic flavouring agents.

In accordance with one preferred embodiment of the present invention,the flavour and aroma of tobacco smoke is improved by adding to thetobacco (which may be natural tobacco or a tobacco substitute of naturalor synthetic origin) a flavouring composition containing at least onecompound selected from the following groups:

1. Amides of formula ##STR1## wherein R and R¹ represent an alkyl radialcomprising 1 to 6 carbon atoms, or a hydrogen atom.

Specific examples of the compounds comprised by formula I include:

    ______________________________________                                        a)  N-isoamylacetamide   Ber., 58, 2017 (1925)                                b)  N-isoamylformamide   Compt. rend.,                                                                  176, 1159 (1923)                                            2. Cycloaliphatic derivatives:                                        ______________________________________                                        a)  3,5,5-trimethyl-cyclohex-2-en-4-                                                                   Tetrahedron, Suppl. 8,                                   ol-1-one             Part I, p. 1 (1966)                                  b)  3,5,5-trimethyl-2,3-epoxy-cyclo-                                                                   n.c.                                                     hexane-1,4-dione                                                          c)  2,6,6-trimethyl-cyclohex-2-en-4-ol-                                                                n.c.                                                     1-one                                                                     d)  4,4,6-trimethyl-cyclohexa-2,5-dien-                                                                n.c.                                                     2-ol-1-one                                                                e)  3,5,5-trimethyl-cyclohex-3-en-1-yl                                                                 n.c.                                                     acetate                                                                   f)  3,5,5-trimethyl-4-hydroxy-4-[but-1-                                                                J.Org.Chem., 33,                                         en-3-one]-cyclohex-2-en-1-one                                                                      3566 (1968)                                          g)  3,5,5-trimethyl-2-hydroxy-cyclohex-                                                                Phytochemistry, 10,                                      2-ene-1,4-dione      2755 (1971)                                          h)  3,5,5-trimethyl-cyclohex-2-en-2-                                                                   J.Org.Chem. 24, 719                                      ol-1-one             (1966)                                                       3. Phenol derivatives:                                                ______________________________________                                        a)  2-hydroxy-5-methyl-acetophenone                                                                    c.a.                                                 b)  2-methyl-5-isopropenyl-anisole                                                                     Helv. Chim. Acta, 48,                                                         1057 (1965)                                                  4. Heterocyclic ketones of formula                                    ______________________________________                                         ##STR2##                     II                                              ______________________________________                                    

containing a double bond in one of the positions indicated by the dottedlines, and wherein X represents either a hydrogen atom or a hydroxylgroup when the double bond is in the ring, or an oxygen atom when thedouble bond is external to the ring, R² and R³ represent a lower alkylsubstituent, and Z stands for oxygen or sulphur.

Specific examples of compounds comprised by the above indicated formulainclude:

    __________________________________________________________________________    a)                                                                              2,5-dimethyl-4,5-dihydrofuran-                                                                  Swiss patent No. 474,500                                    3-ol-4-one                                                                  b)                                                                              2,5-dimethyl-4,5-dihydrothio-                                                                   D.O.S. No. 1,932,800                                        phen-3-ol-4-one                                                             c)                                                                              2-methyl-5-ethyl-4,5-dihydro-                                                                   Swiss patent No. 491,904                                    furan-3-ol-4-one                                                            d)                                                                              2-ethyl-5-methyl-4,5-dihydro-                                                                   Swiss patent No. 491,904                                    furan-3-ol-4-one                                                            e)                                                                              2,5-dimethyl-2,3-dihydrofuran-                                                                  Helv.Chim.Acta, 46, 1259 (1963)                             3-one                                                                       5. Caryophyllene derivatives:                                                 a)                                                                              caryophyllenepoxide of formula                                               ##STR3##                                                                                         Helv.Chim.Acta, 51, 494 (1968)                            b)                                                                              and c) caryophyllene alcohols of formula                                     ##STR4##                                                                                         Helv.Chim.Acta, 51, 494 (1968)                            6. Miscellaneous                                                              a)                                                                              epoxy-β-ionone                                                                             Helv.Chim.Acta, 29, 1829 (1946)                           b)                                                                              6-methyl-hepta-3,5-dien-2-one                                                                   USSR patent No. 138,612                                   c)                                                                              3-isopropyl-cyclopent-2-en-1-one                                                                J.Org.Chem., 33, 1656 (1968)                              d)                                                                              octa-3,5-dien-2-one                                                                             Belgian patent No. 660,099                                e)                                                                              nonane-2,5,8-trione                                                                             Ber., 76, 183 (1943)                                      f)                                                                              2-methyl-5-(α-methyl-α-hydroxy-                                                     Ber., 38, 1719 (1905)                                       ethyl)-cyclohex-2-en-1-one                                                  g)                                                                              4-methylthiobutan-2-one                                                                         C.A., 52, 9141e (1958)                                    __________________________________________________________________________

In the hereinabove list of compounds of the groups 1 to 6, immediatelyfollowing the chemical name of each member there is given the commercialsource or a literature reference giving a method for its preparation.Commercially available products are identified by the abbreviation c.a.,and may be obtained from FLUKA A. G., Buchs S. G., Switzerland; ALDRICHCHEM. CO., Milwankee, Wis.; or K. & K. LABORATORIES INC., Mainview, N.Y.11803.

In those instances wherein new compounds are described a detailed methodof preparation is given in the course of this description or in one ofthe examples. New compounds are identified by the abbreviation n.c.

The results of the organoleptic evaluation tests are set out in thespecific examples.

An additional object of the present invention is to provide compositionsfor flavouring tobacco or tobacco substitutes comprising at least onecompound selected from the groups listed above.

The compounds listed above have been divided into groups based more onsimilarities of their chemical structure than on their specificorganoleptic properties. The wide range of organoleptic propertiesassociated with the compounds described above makes it possible toachieve a variety of effects depending on the nature of the individualcomponents used in a given aromatic mixture.

The compounds and/or flavouring compositions described herein may beused in a variety of forms. It is preferable, however, to utilize thesecompounds or compositions in the form of solutions thereof. The chemicalnature, solubility and stability determine the form in which a givencompound or composition is to be employed.

A convenient method for flavouring tobacco consists in spraying thetobacco with an alcoholic solution of the compound or flavouringmixture. Combinations of solvents such as alcohol and propylene glycolmay also be used.

The proportions of the new compounds to be used in said compositions orin accordance with the process of the present invention can vary withinwide limits. Said proportions depend particularly on the specificorganoleptic effects it is desired to achieve and on the origin of thetobacco products to which the mentioned flavouring ingredients areadded. For instance, interesting flavouring effects can be achieved withamounts ranging from 1 to 1000 ppm, based on the weight of the productflavoured. However, special effects may be achieved by proportions ashigh as 5 or even 10 %. Typically, proportions comprised in betweenabout 10 and 200 ppm are preferably used.

In all cases, the ranges given above may be varied, depending upon thespecific odoriferous or flavouring effect it is desired to achieve.

A further object of the present invention is to provide a process forthe preparation of a new cyclic ketone, the4,4,6-trimethyl-cyclohexa-2,5-dien-2-ol-1-one. The process in accordancewith the invention comprises treating isophorone with a halogenatingagent, such as for example N-bromosuccinimide, to afford a3,5,5-trimethyl-4-halocyclohex-2-en-1-one, and oxidizing the ketone thusobtained by means of a tertiary amine oxide, such as trimethylamineoxide.

The above mentioned process is better illustrated by the followingreaction scheme: ##STR5##

The use of tertiary amine oxides for promoting the oxidation ofhaloderivatives is known and described in the chemical literature [seefor example Berichte der Chemie, 94, 1360 (1961)]. In agreement with theprior art teachings, said oxidation was expected to proceed through aquaternary salt intermediate having the formula ##STR6## to yield asfinal product a cyclohexane-1,4-dione. We have unexpectedly found thatby the oxidation of 3,5,5-trimethyl-4-halocyclohex-2-en-1-one, inacocordance with the process of the present invention, a 1,2-dionederivative was formed instead. Said diketone was in equilibrium with itsketo-enol form according to the above given scheme.

The present invention relates further to the new compounds which havebeen listed above.

Said compounds may be prepared in accordance with the methods describedhereinbelow:

2. (b) 3,5,5-Trimethyl-2,3-epoxy-cyclohexane-1,4-dione

2 ml of a 6 N aqueous solution of NaOH have been added during a periodof 15 minutes at 15° C. to a mixture of3,5,5-trimethyl-cyclohex-2-en-1,4-dione (3.7 g) and hydrogenhydroperoxide (8.3 ml of a 30 % solution) in 27 ml of methanol. Themixture was kept under stirring during 3 hours at 20°-25° C., treatedwith water and extracted with ether. The combined organic extracts werewashed with water until neutrality, dried over MgSO₄ and evaporated.3.33 g (81.5 %) of the desired product, b.p. 40° C./0.001 Torr, werethus obtained.

IR: 1715 cm⁻ ¹ ;

MS: M⁺ = 168; m/e: 56

NMR (CCl.sub. 4): 1.05 (3H,s); 1.25 (3H,s); 1.50 (3H,s); 2.08 (1H,d,J=13 cps); 3.09 (1H,d, J=13 cps); 3.47 (1H,s) δ ppm.

3,5,5-Trimethyl-cyclohex-2-en-1,4-dione, used as starting material forthe above described preparation, may be obtained in accordance with theprocedure described in Tetrahedron, Suppl. 8, Part I, p. 1 (1966).

2. (c) 2,6,6-Trimethyl-cyclohex-2-en-4-ol-1-one

Prepared in accordance with the procedure described in Tetrahedron,Suppl. 8, Part I, p. 1 (1966), starting from isophorone.

In addition to the ketal intermediate of formula ##STR7## as described,we have obtained a ketal of formula ##STR8## which has been separated bycolumn chromatography on silicagel (elution: benzene+ ethyl acetate).

Ketal (b) has been reduced by LiAlH₄ in ether solution and the productthus obtained directly hydrolysed in a mixture of dioxane and 5 % H₂ SO₄at 20° C.

NMR (CCl₄): 1.10 (6H,s); 1.72 (3H,s); 1.85-2.40 (2H,m); 4.50 (2H, sbroad); 6.64 (1H, s broad) δ ppm.

2. (d) 4,4,6-Trimethyl-cyclohexa-2,5-dien-2-ol-1-one

Prepared according to Example 2.

2. (e) 3,5,5-Trimethyl-cyclohex-3-en-1-yl acetate

Prepared by reduction by means of sodium borohydride in methanol ofβ-isophorone [obtained according to J. Am. Chem. Soc., 63, 2308 (1941)[and subsequent acetylation of the obtained3,5,5-trimethyl-cyclohex-3-en-1-ol by means of acetic anhydride in thepresence of sodium acetate at 50° C. during 20 hours.

NMR (CCl₄): 1.0 (6H,s); 1.62 (3H,s); 1.92 (3H,s); 5.10 (1H,s); 4.6- 5.2(1H,m) δ ppm

The invention also relates to a method for modifying, improving orenhancing the organoleptic properties of foodstuffs, feedstuffs,beverages and pharmaceutical preparations, which comprises adding tosaid materials a small but effective quantity of at least one compoundselected from the class consisting of group 2 and the following group:3,5,5-trimethyl-cyclohex-2-ene-1,4-dione,2,2,6-trimethyl-cyclohexan-4-ol-1-one,3,5,5-trimethyl-cyclohexan-4-ol-1-one,3,5,5-trimethyl-4-methylene-cyclohex-2-en-1-one and3,5,5-trimethyl-cyclohexane-1,4-dione. The preparation of thehereinabove mentioned compounds has been described in U.S. Pat. LetterNo. 3,380,456.

We have surprisingly found that whenever said compounds wereincorporated to said materials or to flavouring compositions containingamong their ingredients phenol or phenol derivatives, the harshness andthe chemical character of their phenolic taste was reduced or evensuppressed.

Such a finding is of great interest to the flavour industry,particularly for modifying the roasted character of the taste of certainbeverages such as infusions or decoctions prepared from tea, coffee,lime-blossom tea. Moreover, their use is particularly interesting forthe flavouring of meat, more specifically of smoked meat, of roastedcereals and roasted nuts. When taken separately, said compounds can alsoimpart to the products to which they are added a caramel- or straw-likecharacter and find a useful application in the flavouring of infusionsor decoctions and certain fermented foodstuffs in general.

The proportions previously indicated for tobacco flavouring equallyapply for the use of the above compounds in accordance with thehereinabove described method. For the purpose of the presentspecification, the term "foodstuff" is used broadly; and it is deemed toindicate also products such as coffee, tea and cocoa.

The invention is better illustrated by the following examples.

EXAMPLE 1

7 g of a 1 % alcoholic solution of3,5,5-trimethyl-2,3-epoxy-cyclohexane-1,4-dione (in 95 % ethyl alcohol)were sprayed onto a mixture of tobacco of "american blend" (100 g). Thetobacco thus flavoured was used to manufacture "test" cigarettes, thesmoke of which was then subjected to organoleptic evaluation bycomparison with non flavoured cigarettes ("control"). The tobacco usedto prepare the "control" cigarettes was preliminarily treated with 95 %ethyl alcohol.

The panel of experts unanimously defined the taste of the "test"cigarettes as being sweeter than that of the "control" cigarettes;moreover, the smoke possessed a note with an improved herb-likecharacter and was reminiscent of the taste of cigar smoke.

By following the same procedure as that given in above Example 1, othersamples were evaluated. The hereinbelow table gives the list of thetested compounds as well as the quantities employed and the flavoureffect observed.

                                      TABLE                                       __________________________________________________________________________    Compound                                                                             Amount [g].sup.(1)                                                                    Organoleptic Evaluation.sup.(2)                                __________________________________________________________________________    1. a)  1.0 - 10.0                                                                            Nutty, chocolate taste                                         1. b)  1.0 - 10.0                                                                            Rich nutty taste; sweet flue-cured character; chocolate;                      adds body                                                      2. a)  1.0 - 10.0                                                                            Sweet, flue-cured character                                    2. b)    "     Sweet, phenolic flue-cured character; some nutty chocolate                    taste                                                          2. c)    "     Flue-cured character; slight nutty, phenolic taste; some                      ionone character                                               2. d)  7.0     Sweet, woody character; anise-like note; more pleasant         2. e)  1.0 - 10.0                                                                            Sweet, woody, flue-cured character                             2. f)  1.0 - 10.0.sup.(3)                                                                    Sweet, flue-cured character                                    2. g)  1.0 - 10.0                                                                            Sweet, woody, herb-like                                        2. h)  1.0 - 10.0                                                                            Sweet, herb-like                                               3. a)  1.0 - 10.0                                                                            Rich sweet, nutty taste; adds flue-cured character             3. b)    "     Phenolic taste; slight Burley effect                           4. a)  0.5     Sweet, slightly woody, caramel and honey-like                  4. b)  1.0     Fruity, woody, slightly sulphur-like                           4. c)  1.0 - 5.0                                                                             Sweet, caramel                                                 4. d)    "     Sweet, caramel                                                 4. d)  0.1 - 0.5                                                                             Caramel                                                        5. a)  1.5 - 2.5                                                                             Woody, cigar smoke-like; orient tobacco note                   5. b) and c)                                                                         2.5 - 5.0                                                                             as above                                                       6. a)  1.0     Sweet, nutty, chocolate taste; adds body; some flue-cured                     character                                                      6. b)  10.0    Sweet, nutty, chocolate taste; adds body                       6. c)  10.0    Sweet, green note                                              6. d)  10.0    Adds body; flue-cured flavour note                             6. e)  10.0    Sweet, nutty, chocolate taste; some flue-cured character       6. f)  10.0    Flue-cured character, phenolic; nutty, chocolate taste;                       adds body                                                      6. g)  10.0    Some Burley character                                          __________________________________________________________________________     .sup.(1) The amounts indicated refer to the quantities of a 1 % alcoholic     solution (95 % ethyl alcohol)?                                                .sup.(2) The characters given refer to specific flavour properties of the     tested compounds on tobacco as compared with a non flavoured tobacco.         .sup.(3) The amount indicated refers to the quantities of a 2 % alcoholic     solution (95 % ethyl alcohol).                                           

EXAMPLE 2

(a) A mixture of isophorone (13.82 g; 0.1 Mole) and N-bromo-succinimide(17.80 g; 0.1 Mole) in the presence of traces ofα,α'-azodiisobutyronitrile was refluxed in 500 ml of CCl₄ during 15minutes. 500 ml of petrol-ether (30°-50° C.) were then added to the coolreaction mixture and the succinimide thus precipitated was filtered off.By evaporating the volatile components of the clear filtrate, crude3,5,5-trimethyl-4-bromo-cyclohex-2-en-1-one was obtained.

NMR (CCl.sub. 4): 1.16 (3H,s); 1.25 (3H,s); 2.11 (3H,s); 2.07 (1H,d,J=16 cps); 2.53 (1H,d, J=16 cps); 4.45 (1H,s); 5.78 (1H,s) δ ppm.

(b) During a period of 30 minutes3,5,5-trimethyl-4-bromo-cyclohex-2-en-1-one (43.4 g) was added to asolution kept at 40° C. of anhydrous trimethylamine N-oxide (32 g) in100 ml of anhydrous chloroform. The reaction was slightly exothermic andthe temperature of the mixture was kept at 45°-50° C. by externalcooling during the whole addition. After cooling to room temperature,said mixture was poured onto 110 ml of 10 % H₂ SO₄ and the organiclayers which separated were washed with water (3 ×), a 10 % solution ofsodium carbonate (3 ×) and finally with water again (3 ×) untilneutralisation.

By evaporation of the volatile components, and subsequent distillationof the resulting residue a product was obtained at b.p. 47°-60° C./0.001Torr. This product was treated with petrol-ether (30°-50° C.) and thensuccessively washed with a 5 % aqueous solution of sodium carbonate (2×) and a 2 % aqueous solution of NaOH (5 ×). The mother liquors wereacidified and immediately extracted with diethyl ether.

The combined extracts were washed, dried over MgSO₄ and evaporated atreduced pressure. 8 g of the desired product were thus obtained (95 %purity). The subsequent purification was carried out by sublimation at70°-80° C./ 10 Torr, and yielded 6 g of pure4,4,6-trimethyl-cyclohexa-2,5-dien-2-ol-1-one. The product had apositive test when treated with a solution of ferric chloride(blue-violet colour); m.p. 46° C.

IR (CCl₄): 1630, 1650 3440 cm⁻ ¹

UV: λ _(max).sup. EtOH = 205, 249, 310 mμ (ε=5650, 7880, 2420respectively)

MS: M⁺ = 152; m/e: 109

NMR (CCl₄): 1.27 (6H,s); 1.92 (3H,s); 5.97 (1H, pseudo d, J= ca. 2.5cps); 6.34 (1 H, m); 6.65 (1H,m) δ ppm.

Under the conditions used for carrying out the above given analysis, thecompound showed a keto-enol structure represented by the followingformula ##STR9## However, under other conditions it is reasonable toassume that the keto-enol equilibrium may be in favour of a diketonicstructure according to the following equation: ##STR10##

By replacing trimethylamine oxide by other tertiary aliphatic orcycloaliphatic amine oxides analogous results were achieved. Further,halogenating reagents other than N-bromo-succinimide, able to affordpositive halogens, may be used for promoting the halogenation step.

EXAMPLE 3

The following flavouring compositions were prepared by admixing (partsby weight):

    ______________________________________                                                      A (control)                                                                            B      (test)  C                                       ______________________________________                                        p-ethylguaiacol 1 % *                                                                          10        10           20                                    guaiacol 1 % *   15        15           30                                    3,5,5-trimethyl-cyclohexane-                                                  1,4-dione 10 % *                                                                               --        30           30                                    95 % ethyl alcohol                                                                             975       945          920                                                   1000       1000         1000                                  ______________________________________                                         * in 95 % ethyl alcohol                                                  

Flavours A, B and C were then compared in a concentration of 0.06 g offlavour for 60 ml of sugar syrup (prepared by dissolving 650 g ofsucrose in 1350 ml of water).

The finished syrups were tested by a panel of qualified tasters whoexpressed their views on the value of the flavours used for theirpreparation. These persons declared unanimously that the taste of thesyrup which had been flavoured with composition B had a more diffusenote than the syrup flavoured with composition A; moreover, the typicalphenolic character shown by this latter syrup was well masked. By usingcomposition C, analogous results were obtained although less pronounced.

Flavours A, B and C were then compared in a concentration of 0.06 g offlavour for 60 ml of salt solution (prepared by dissolving 0.5 g of NaClin 100 ml of water).

In this case also the flavour experts declared that the taste of thebeverages which had been flavoured with compositions B and C lacked thephenolic character of the beverage flavoured with composition A.

EXAMPLE 4

The following flavouring compositions were prepared by admixing (partsby weight):

    ______________________________________                                                      A (control)                                                                            B      (test)  C                                       ______________________________________                                        p-ethyl phenol 1 % *                                                                           10        10           20                                    phenol 1 % *     15        15           30                                    4,4,6-trimethyl-cyclohexa-                                                    2,5-dien-2-ol-1-one 10 % *                                                                     --        30           30                                    95 % ethyl alcohol                                                                             975       945          920                                                   1000       1000         1000                                  ______________________________________                                         * in 95 % ethyl alcohol                                                  

The above given flavours were then compared in a sugar syrup and in saltaqueous solution exactly as indicated in Example 3. The flavour expertsdeclared that the taste of the beverages which had been flavoured withcompositions B and C lacked the phenolic taste note of the beveragesflavoured with composition A; the overall note was more rounded-off andpossessed a better flavour harmony.

By replacing 4,4,6-trimethyl-cyclohexa-2,5-dien-2-ol-1-one by3,5,5-trimethyl-2,3-epoxy-cyclohexane-1,4-dione,2,6,6-trimethyl-cyclohex-2-en-4-ol-1-one,3,5,5-trimethyl-cyclohex-3-en-1-yl acetate,3,5,5-trimethyl-4-hydroxy-4-[but-1-en-3-one]-cyclohex-2-en-1-one,3,5,5-trimethyl-cyclohex-2-ene-1,4-dione,3,5,5-trimethyl-cyclohex-2-en-4-ol-1-one,2,2,6-trimethyl-cyclohexan-4-ol-1-one,3,5,5-trimethyl-4-methylene-cyclohex-2-en-1-one,3,5,5-trimethyl-2-hydroxy-cyclohex-2-ene-1,4-dione,3,5,5-trimethyl-cyclohexan-4-ol-1-one,3,5,5-trimethyl-cyclohexane-1,4-dione or3,5,5-trimethyl-cyclohex-2-en-2-ol-1 -one.

I claim:
 1. A process for improving, enhancing or modifying theorganoleptic properties of a tobacco product, which comprises addingthereto about 1 to about 1000 parts per million based on the weight oftobacco of octa-3,5-dien-2-one.
 2. A tobacco or tobacco product havingadded thereto about 1 to about 1000 parts per million based on theweight of tobacco of octa-3,5,-dien-2-one.
 3. A tobacco flavouringcomposition which comprises octa-3,5-dien-2-one.